This present invention relates to power management in data centers and large server environments.
Servers and other information technology equipment consume large amounts of energy and create large amounts of heat even when idle or lightly used. Large applications like online banking, search or news web sites, amongst others and virtualized application environments typically require multiple servers within a single data center or spread across different data centers that are physically placed in different locations to support heavy load, reduce the risk for outages and provide response times that cannot be achieved with use of a single server. Such response time and availability is defined with service levels that set acceptable response time and availability for each application. To maintain service levels all servers usually run 24 hours a day, 7 days a week to ensure that during peak demand the overall application still meets such performance levels and load never exceeds available capacity. However, usual average monthly utilization of these servers may well be as low as 4% with a couple of short peaks that bring utilization up to 80-90%.
In addition to the power consumption of the servers and other information technology equipment, such equipment also generates large amounts of heat that requires active cooling. For every Watt of power consumed by any such equipment, data centers have to factor in an additional 20% to 200% of power consumption for cooling services. Using outside air can bring this energy requirement down, whereas heavy air conditioning can increate it in warmer regions.
Looking to the power consumption of servers and other information technology equipment shows that any equipment requires power as soon as it is plugged into an outlet. The amount of power when the equipment is turned off (“off state”) can be anywhere from 1% to 25% of its maximum power consumption under full load. Equipment is turned on and it runs through its startup sequence and settles at an “idle state”—a state at which no application functionality is executed but the operating system is up and running. When applications are running and application load is added to the equipment, the power consumption will increase up to a maximum power consumption (“loaded state”) at which the equipment runs at peak performance and performs at maximum capacity/efficiency. During any type of intermediate load, power consumption fluctuates between idle and loaded levels. Idle power consumption typically exceeds 60% of loaded power consumption and can be as high as 90% depending on the type of equipment used and as a result the additional power required to add load is relatively small compared to the power used by equipment that is just turned on but in an idle state.
While power consumption is related to the equipment and load levels of such equipment, the additional power for cooling as well as the cost of power depends primarily on the location of the data center where the equipment is placed. As network distance is a factor in response time and latency and also influences service levels, it is not always possible to pick a data center location with the lowest power cost. Furthermore the cost of power increases continuously due to shortage and an overall increase in worldwide demand.
While there are various methods and systems that can help reduce the power consumption of equipment like: more efficient hardware, power capping, sleep mode, stopping (parking) of hard-disks when idle, and other hardware related solutions, they all focus solely on the reduction of power consumption of a single device. Another method and system used to reduce power consumption is virtualization that allows consolidating the total number of servers and allows combining multiple applications onto a single server, as a result of the reduced number of servers, the power consumption of such a group of servers will also be reduced. Even after all the efficiency improvements undertaken, the fundamental high power consumption of an idle piece of equipment relative to its loaded power consumption is still the same, because of the relatively high power use at an idle state.
To solve the limitations of prior art, this method and apparatus takes a holistic approach by looking at a complete application environment with servers and equipment in a variety of locations that can be optimized together within and across facilities. Furthermore this invention dynamically and automatically adds and removes equipment from an application depending on load and physically turns off equipment when not needed and then back on as demand rises. The result is that invention specified equipment no longer wastes power while idle or close to idle, but instead runs at a more beneficial (e.g. 70% to 80%) average load and invention specified equipment that is not currently needed is physically turned off.